NovoCure’s tumour treating fields (TTFields) failed to recreate its efficacy in previous cancer studies, after the company announced that the therapy did not meet its primary endpoint of overall survival in an ovarian cancer study.

The Phase III trial (NCT03940196) investigated TTFields together with paclitaxel – a standard chemotherapy drug – in patients with platinum-resistant ovarian cancer. According to Novacure, this group makes up around 20% of all ovarian cancer patients.

A total of 540 patients were enrolled in the INNOVATE-3 study, with participants randomised into two groups receiving either paclitaxel and TTFields – via the NovoTTF-100L(O) device – or paclitaxel only.

When comparing the two groups, the analysis showed little difference in survival rates. The group that received both therapies had a median survival rate of 12.2 months versus 11.9 months in the paclitaxel-only group.

Novocure did highlight an exploratory sub-analysis that showed a potential survival benefit in patients who received only one prior line of therapy. The Swiss oncology company said this could warrant further investigation.

Novacure’s NovoTTF-100L system is a US Food and Drug Administration (FDA)-approved device for the treatment of unresectable, locally advanced or metastatic, malignant pleural mesothelioma. The device administers electric fields that can kill cancer cells by physical forces. TTFields is a non-invasive therapy that leaves healthy cells alone and can be used in combination with other treatments due to its targeted approach.

William Doyle, Novocure’s executive chairman said: “While today’s update is disappointing, we are encouraged by the signal identified from the exploratory analysis which suggests the potential for a clinical benefit when TTFields therapy is initiated early in a patient’s treatment journey.”